THERMOGRAPHIC ANALYSIS OF ELECTROMIGRATION PHENOMENA IN ALUMINUM METALLIZATION

Electromigration-induced void growth in Al metallization was investiga ted by comparing it with the electrical resistance change and the ther mographically measured change in temperature distribution. Constant cu rrent flowing through two different-width interconnects in series cons istently induced void growth at their junction so that it could be obs erved with high resolution in the fixed fields of an infrared microsco pe and an optical microscope. The electrical resistance change occurri ng as a result of an electromigration test was found to directly refle ct a local temperature change resulting from the void growth: a pulse phenomenon in the electrical resistance corresponds to a temperature i ncrease of more than 200 degrees C around the void-growing area. This phenomenon can be attributed to a local melting induced by the void gr owth and to a void healing process after recrystallization of the adja cent Al grains. (C) 1996 American Institute of Physics.